Harold wkslock fletcher



6 1927. Sept H. w. FLETCHER COMBINED WASHER AND SHIELD FOR DRIL LS iled May 15. 1926 Patented Sept. 6, 192?.

PATENT OFFICE.

HAROLD W'EUITELOCK FLETCHER. 0F HOUSTON, TEXAS, ASSIGNOR TO HUGHES TOOL COMPANI, OF HQUSTON TEXAS, A CORPQRATION OF TEXAS.

COMBINED WASHER AND SHIELD FOR Application filed May 13, 19:28. Serial No. 108,825.

his invention relates to washers to be rmp|o \'ud on earth boring drills of the hard formation type ordinarily called cone bits.

()n such drills there is a longitudinally dlvidcd head, the lowc ;n(l of which is cleft to form a V shaped slot. Rolling cone shaped cutters are journalled for rotation upon shafts projecting from the 0 posite faces of the slot. These cutters prcihrably have bearing washers thereon, separating them from the head. It is a feature of this type of drill that the flushing fluid, coming down through the central water tube in the head, strikes the or 21s and forms eddies and is deflected so as to force sand and other abrasive material against the side faces, thus causing wear on the head above the cutters and ultimately requiring repair, or,

the head must be discarded.

It is an object of my invention to provide a washer for the rolling cutters which may be extended above the cutters and thus provide a renewable shield for the lower head of the drill.

It is desired to shape the two opposite washers so that they will fit together at their upper ends and protect the entire base of the head from wear of the mud and the-abrasive material disintegrated by the drill.

at'erring to the drawings herewith, Fig. l la broken side view, partly in elevation and partly in central longitudinal section of the lower end of a cone employing my invention; F ig. 2 is a plan view of my combined washer and shield. Like numerals refer to like parts in both views.

In the drawing the lower end of a well known type of well: drillis shown. The head 1, has the usual slot transversely thereof like an inverted V. Cutter supportin pins 2 are formed integrally with the hea said cutter pins being set-at right angles to the side-faces 3, of the slot and adjacentthe lower edge, and are threaded to receive a bushing 4, for the rotatable cutter 5.

The bushing and cutterare preferably separated from the head by a bearing Washer and I have shown my ini roved washer plate 6. Its shape is shown in ig. 2, the lower end 7 being rounded to conform to the shape of the head from the side of which it projects slightly. It has an opening 8 to receive the cutter pin 2. tlutrally of the opposite or upper end of the plate is a notch or recess 9, the inner side of which is cut on the aroot a circle and beveled slightly at 10 to allow the free passage of flushing fluid coming down through the tube 11 axially of the drill. The sides of the recess bear against the lower endof the tube 11 and the upper ends of the two plates are beveled at 12 so that the opposite plates may fit. together at this line.

Between the notch 9 and the opening 8 is an opening 13 of small diameter to receive a dowel pin 14 upon the head to prevent any tendency of the plate to rotate with the cutter 5 in use.

The bushing 4 is frusto-conical on its forward end and has a neck 15 of reduced diameter on its inner end about which tits a locking ring 16 which screws into the end of the cutter and holds it from removal. Said ring, 16 is held from removal by wclding at 17, as shown.

In use, the ashers cover the face of the lower end of the drill head and as the washers are of hardened steel, they protect the head from the wear commonly ox crienced with this type of drill. Flusiing fluid ordinarily containing sand'and abrasivc substances, is pumped down through the tube 11 upon the cutters and the bottom of the hole. Some wea r occurs upon the washers (i but as they are easily removable and replaceable, the drill may be protected from wear at this point indefinitely. Obviously the washer will serve as a bean ing for the cutter in the same way as the usual circular plate commonly employed. The shape ofthe device tends to hold it from rotation through contact of the oppo site plate at 12 when rotation is started. The plates serve effectively as combined washers and shields or protectors.

Having thus described my invention, what I claim as new is:

1. In an earth boringdrill having a head with rotary cutters thereon, and a flushing channel longitudinally of said head. the combination of a air of washer plates fitting between sai cutters and said head, said plates also covering approximately the entire lower end of said drill and acting as a we?" shield therefor.

2. In an earth boring drill having two opposite inwardly and upwardly inclined lower taces'and cutters journalled for rotation on each face, the combination of washers between said cutters and said faces and shaped to fit together at their upper ends to shield the said faces from wear.

7 3. In an earth boring drill having a V- shaped groove transversely of its lower end and cutter pins projecting from the side walls of said groove, the combination of washers fitting about said pins and covering the walls of said recess, cutters on said pins, and means to prevent rotation of said washers, and washers having their adjacent upper ends fitting together to further resist rotation thereof.

4. A washer plate for roller earth boring drill heads, having cutter pins thereon and 15 a flushing channel axially thereof, comprising a plate of wear resisting metal designed to fit beneath one of the cutters of said drill and cover one half .of the lower face of the drill head, to prevent wear on said face in use, said plate having a cutter pin receiving opening and an upper recess to fit about the flushing channel.

In testimony-whereof, I herednto affix my signature this the 10th day of May AMI meow wumocx musse 

